I would agree that in terms of relative guilt that actually raping a child may be worse than not preventing the rape of a child. But the difference is only in degree.
One is a crime and a sin of commision the other is a sin (possibly a crime) of ommision. Both are despicable.
PS
You might consider changing your avatar. I read that the Dalai Lama recently said that he is a Marxist. Its hard to believe, considering what the communist Chinese did to Tibet.
PPS
Are you actually in Nigeria?